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Photosynthetically active radiation (PAR) is the spectral range from 400-700nm that is used by plants in photosynthesis

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Nikon Lens Versions and Serial Nos - photosynthesis…

Photosynthetically Active Radiation (PAR). It’s the basic energy to produce biomass which affects the growth, development, yield and quality of plants directly. PAR defines what’s kind of light source can support plant photosynthesis. The wavelength range of light source to promoting green growth is more wider than photosynthetically active radiation wavelength range, it is roughly at the 300nm to 800nm range, this part of radiation called physiological radiation. Besides it can promote photosynthesis, it also affect other physiological activities.

(PAR) defines radiation from the 400 to 700 nanometer (nm) range that drives photosynthesis

This measure of visible light (i.e., light visible to the human eye) does not exactly correspond to the spectrum of light energy used by plants in photosynthesis (the range of 400 to 700 nm wavelengths, termed "photosynthetically active radiation or PAR")

Photosynthetically Active Radiation (PAR) - Biospherical

Photosynthetically Active Radiation (PAR) is the amount of light available for photosynthesis, which is light in the 400 to 700 nanometer wavelength range.

Photosynthetically Active Radiation or PAR refers to radiation with wavelengths between 400 and 700 nm. The term PAR has been applied to both energy and photon fluxes. The most common use today refers to total photon flux between 400 and 700 nm. The data set indicated with the solid black line in Fig. 1 shows the ideal relative response of a PAR sensor in terms of sensitivity to photons: the sensor has no sensitivity below 400 nm and above 700 nm, and a constant sensitivity from 400–700 nm. The spectral response of PAR sensors offered by Biospherical Instruments mimics this function (orange symbols in Fig. 1).

The problems with this type of measurement are that it is an instantaneous measurement and plants do not use the green waveband.What is Photosynthetic Active Radiation (PAR)?PAR is the amount of light energy within the 400-700 nm wavelength range used by plants for photosynthesis.

Light Unit Conversion Table | parsource

Photosynthesis active radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynth…

The measurement of the amount of light that we give to our plants is called PAR (Photo-synthetically Active Radiation). This is a measurement of the amount of photons that a plant can use to photosynthesise with in a given area in a certain length of time. It is measured in something called PPFD (Photosynthetic Photon Flux Density) and the unit of measurement of PPFD is micromoles per square metre per second (umol/m2/s). It is measured between the wavelengths of 400nm to 700nm. There is no weighting given to one particular colour or wavelength range. All photons in the range 400nm to 700nm are counted the same:

For this reason it is noteworthy that while any light within the PAR range can be used, providing light energy outside certain proven/evolved aspects of PAS can result in poor growth or allowing of less desirable algae to out compete plants or coral we are attempting to cultivate. This why it is a FACT that while certain lights may keep photosynthetic life, less than optimum spectrums found in many of the inferior lights will either produce lessor results and/or require more input light energy for the same results as say a high PAS & PUR light such as the AAP AquaRay.

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Plant Science SUNMASTER Infrared UV Photosynthesis …

PAR is the abbreviation for Photosynthetically Active Radiation which is the spectral range of solar light from 400 to 700 nanometers that is generally accepted as needed by plants & symbiotic zooanthellic algae for photosynthesis (Zooxanthellae are single-celled algae that live in the tissues of animals such as corals, clams, & anemones).
It is also noteworthy that while outside of the accepted PAR, a study using infrared (IR) LEDs of 880 nm & 935 nm on etiolated oat seedlings showed leaf emergence, so these parameters may someday need better defining (See at the end of article).

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